Glycerin burning system

ABSTRACT

A glycerin burning system having a specialized atomizing burner capable of combusting a continuous feed of crude or pure glycerin. The burner includes a two-fluid mixing nozzle. The nozzle has an internal distributor which mixes two fluid feed streams as the fluids are expelled through an orifice. The distributor has channels which cause the air to swirl before mixing with the glycerin. An impingement pin is provided outside the orifice to diffuse the mixture and reduce combustion air speed. To improve performance, the burner&#39;s air feed line is subjected to combustion chamber to preheat the air passing through the feed line before the air is mixed with the glycerin.

CROSS-REFERENCES TO RELATED APPLICATIONS

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STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

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MICROFICHE APPENDIX

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BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to the field of waste product combustion. More specifically, the present invention comprises a glycerin burning system having a specialized atomizing nozzle for the combustion of glycerin.

2. Description of the Related Art

Glycerin, or glycerol, is a byproduct of biodiesel and soap manufacturing. Although there are various uses for pure glycerin, the increase in demand for biodiesel has resulted in the production and stockpiling of large quantities of crude glycerin. This trend is expected to continue.

Currently there is a need for effective combustion systems for the disposal and heat recovery of glycerin. The most effective glycerin combustion systems typically require a substantial amount of combustion enhancer (an alternate fuel source) to be added to the glycerin in order to achieve the complete combustion of the glycerin. This adds significant cost to the process.

Existing burners cannot burn pure glycerin because the combustion air speed produced by conventional burners exceeds the flame propagation speed of the air-glycerin mixture. Even if one is able to instantaneously ignite the air-glycerin mixture the flame will be quickly blown away by the burner. This phenomenon is a major obstacle to the development of effective glycerin combustion systems.

Accordingly, it would be desirable to have a glycerin burning system which is not costly to operate and is capable of completely combusting a feed of crude or pure glycerin.

BRIEF SUMMARY OF THE INVENTION

The present invention comprises a glycerin burning system having a specialized atomizing burner capable of combusting a continuous feed of crude or pure glycerin. The burner includes a two-fluid mixing nozzle or a one fluid impingement nozzle. The nozzle has an internal distributor which mixes two fluid feed streams (glycerin and air) as the fluids are expelled through an orifice. The distributor has channels which cause the air to swirl before mixing with the glycerin. An impingement pin is provided outside the orifice to diffuse the mixture and reduce combustion air speed.

To improve performance, the burner's air feed line exchanges heat with the combustion chamber to preheat the air passing through the feed line before the air is mixed with the glycerin. In addition, a flame retention head is employed on the burner to improve combustion efficiency. Alternate air diversion methods are also proposed for reducing combustion air speed.

In the preferred embodiment, the combustion chamber is first heated to a designated operating temperature by combusting a mixture of glycerin and alcohol before switching to a feed of pure raw glycerin. Upon cessation of combustion operations, the system is purged with water.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a schematic illustration of a glycerin burning system.

FIG. 2 is a side view, showing a burner for use with the glycerin burning system.

FIG. 3 is a side view, illustrating the operation of the burner.

FIG. 4 is an exploded perspective view, showing an impingement mixing nozzle for use with the burner.

FIG. 5 is a perspective view, showing a distributor for use with the impingement mixing nozzle.

FIG. 6 is a section view, illustrating the operation of the impingement nozzle.

REFERENCE NUMERALS IN THE DRAWINGS

10 glycerin burning system 12 combustion chamber 14 wall 16 port 18 conduit 20 burner 22 nozzle 24 port 26 exhaust 28 fuel pump 30 fuel cutoff solenoid 32 air tube 34 impingement pin 36 flame retention head 38 fuel feed 40 check valve 42 purge fluid solenoid 44 ignition transformer 46 manifold 48 check valve 50 starter feed 52 water feed 54 vents 56 orifice 58 conduit 60 receiver 62 distributor 64 fuel feed connector 66 conduit 68 channels 70 swirl channels 72 orifice 74 surface 76 surface 78 combustion zone 80 target surface

DETAILED DESCRIPTION OF THE INVENTION

The present invention, glycerin burning system 10 is illustrated in FIG. 1. Glycerin burning system 10 may be used to burn a continuous feed of raw or pure glycerin. Glycerin burning system 10 generally includes burner 20 which expels glycerin through nozzle 22 into combustion chamber 12 where the glycerin is combusted in combustion zone 78. Exhaust gases are vented to the atmosphere through exhaust 26. Air is fed to burner 20 by a burner air blower and a portion of the air fed to burner 20 is diverted into conduit 18 which wraps around wall 14 of combustion chamber 12. Conduit 18 may be the interior region of a “jacket” surrounding wall 14 or any other conduit suitable for directing the flow of air around combustion chamber 12 while allowing the air to exchange heat with combustion chamber 12. Ports 24 and 16 are provided in wall 14 and direct heated air toward combustion zone 78. The direction of hot air towards combustion zone 78 serves two synergistic functions. First, the hot air helps atomize the glycerin expelled from burner 20. Second, the air flow reduces the effective air velocity of air exiting burner 20. These two functions work together to mitigate “flare out.” Flare out occurs when the combustion air velocity exceeds the flame propagation speed in the glycerin-air mixture.

FIG. 2 illustrates burner 20 in greater detail. Burner 20 includes fuel pump 28 which pressurizes the glycerin feeding into burner 20. During glycerin combustion operations, glycerin passes through fuel cutoff solenoid 30 (when in the open position) through check valve 40 into manifold 46 where it is fed to fuel feed line 38. Ignition transformer 44 provides a spark to ignite the fuel after it exits nozzle 22 and strikes impingement pin 34. Starter feed 50 is provided for supplying a feed of a starter fuel (such as alcohol or an alcohol-glycerin mixture) to burner 20 during start-up. The starter fuel is used to heat the combustion chamber to a designed operating temperature before switching to a pure glycerin feed. The starter fuel is supplied to fuel feed line 38 though check valve 48 and manifold 46. An exterior pump is used to supply the starter fuel to burner 20.

Water is used to purge burner 20, thus cleaning the internal components thereof, upon the cessation of combustion operations. Water is supplied to burner 20 though water feed 52. Purge fluid solenoid 42 regulates the flow of water to burner 20. Like the starter fuel, an exterior pump supplies water to water feed 52.

Air is supplied to burner 20 by a burner air blower. As mentioned previously, a portion of this air feed is directed into the conduit wrapping around the combustion chamber. The other portion is fed into air tube 32. Turning to FIG. 3, a portion of the air fed into air tube 32 is diverted through vents 54 in flame retention head 36. Flame retention head 36 helps provide a broad, stable combustion air flow to promote even flame propagation. As mentioned previously, the glycerin is expelled through nozzle 22 where it strikes the tip of impingement pin 34, diffuses, and mixes with combustion air.

FIG. 4 shows a detailed view of nozzle 22. Nozzle 22 is an internal mix nozzle in which a portion of the combustion air is mixed with the glycerin feed as the glycerin passes through conduit 58 and orifice 56 and strikes impingement pin 34. Distributor 62 rests inside receiver 60. Distributor 62, which imparts rotation to the air feed before the air feed begins mixing with the glycerin feed, is shown in greater detail in FIG. 5. Distributor 62 has fuel feed connector 64 which connects distributor 62 to the fuel feed line of the burner. Fuel passing through the feed line passes through conduit 66 within distributor 62 and out orifice 72. Air passes around distributor 62 through channels 68 into swirl channels 70. Surfaces 74 and 76 mate with the interior of receiver 60 so that air passing around distributor 62 is forced through channels 68 and swirl channels 70. Swirl channels 70 impart rotation to the air feed by directing the air in angularly about the central axis of conduit 66. This rotation aids in the mixing and atomization of the glycerin feed as it exits the nozzle.

FIG. 6 is a section view of nozzle 22 with distributor 62 omitted for greater clarity. Glycerin exiting orifice 72 of conduit 66 is picked up by the rotational air flow passing around distributor. The glycerin passes through conduit and out orifice 56 where it impinges against target surface 80 of impingement pin 34. This diffuses the air-glycerin mixture, reflecting a portion of the stream back onto the stream exiting orifice 56. This creates more collision between glycerin and air particles and greater diffusion around impingement pin 34. This also reduced the velocity of the stream. The glycerin and air mixture passes around impingement pin 34 as a fine mist or fog. Such a nozzle design both reduces combustion air speed and atomizes the glycerin feed for improved flame propagation.

With the various components of the glycerin burning system now described, operation of the glycerin burning system will be described in greater detail. During start-up, starter fuel is fed to burner 20 through starter feed 50. The starter fuel passes through check valve 48 and into manifold 46 before passing through fuel feed 38. Ignition transformer 44 produces a spark as the starter fuel exits nozzle 22. Starter fuel is fed to burner 20 for a sufficient period of time to heat the combustion chamber to the desired temperature.

When the desired temperature is reached, fuel pump 28 feeds fuel to manifold 46 through check valve 40. In order to do this, fuel cutoff solenoid 30 is moved to the open position. The fuel is fed to nozzle 22 where it is atomized and combusted. Check valve 48 prevents the fuel from being forced into starter feed 50.

Upon cessation of combustion operations, fuel cutoff solenoid 30 is moved to the closed position and purge fluid solenoid 42 is opened. Water or other purging fluid is fed to burner 20 via water feed 52. The water passes through purge fluid solenoid 42 into manifold 46. The water then passes out of burner 20 through fuel feed 38 and nozzle 22. This cleans the internal components of burner 20 and nozzle 22 to insure that burner 20 and nozzle 22 will last many burning cycles without “gumming up.” Check valve 40 and check valve 48 prevent the purge fluid from passing back into the fuel and starter fluid feed lines.

The preceding description contains significant detail regarding the novel aspects of the present invention. It should not be construed, however, as limiting the scope of the invention but rather as providing illustrations of the preferred embodiments of the invention. For example, components of the present invention, such as nozzle 22, may be useful in other applications. Thus, the scope of the invention should be fixed by the following claims, rather than by the examples given. 

1. A fuel burning system, comprising: a. a burner, including i. a fuel feed line, configured to supply a fuel to said burner; ii. an air supply line, configured to supply air to said burner; iii. a nozzle configured to atomize said fuel by mixing said fuel with said air from said air supply line, said nozzle having an exterior and an interior, said nozzle further having
 1. a distributor in said interior of said nozzle, said distributor fluidly connected with said fuel feed line and said air supply line;
 2. an orifice in said exterior fluidly connected with said distributor;
 3. an impingement pin attached to said exterior of said nozzle, said impingement pin having a target surface positioned coaxially with said orifice and facing said orifice, said target surface being configured to diffuse an atomized fuel stream expelled through said orifice.
 2. The fuel burning system of claim 1, wherein said nozzle is configured to spray said atomized fuel stream into a combustion chamber where said atomized fuel stream is combusted.
 3. The fuel burning system of claim 1, wherein said fuel comprises glycerin.
 4. The fuel burning system of claim 1, wherein said nozzle is configured to spray said atomized fuel stream into a combustion zone where said atomized fuel stream is combusted; said glycerin burning system further comprising a heat exchanger positioned in said combustion zone, said heat exchanger configured to preheat said air supplied through said air supply line with heat produced from the combustion of said atomized fuel stream before said air is mixed with said fuel.
 5. The fuel burning system of claim 1, further comprising a starter fuel supply line, said starter fuel supply line configured to supply a starter fuel to said fuel feed line so that said starter fuel mixes with said fuel.
 6. The fuel burning system of claim 5, wherein said starter fuel comprises an alcohol.
 7. The fuel burning system of claim 1, said distributor configured to impart vorticity to said air feed.
 8. The fuel burning system of claim 1, said distributor having a fuel conduit fluidly connected to said fuel supply line, a plurality of air channels fluidly connected with said air supply line and a convergence region fluidly joining said plurality of air channels and said fuel conduit upstream of said orifice, said plurality of air channels configured to impart rotation to said air feed before said air feed passes through said orifice.
 9. A method of combusting glycerin, comprising: a. providing a burner, said burner including: i. a fuel supply line, configured to supply said a glycerin feed to said burner; ii. a nozzle, configured to atomize said glycerin feed to produce an atomized glycerin stream, said nozzle having an exterior and interior, said nozzle further having:
 1. an orifice fluidly connected with said fuel supply line and adapted to expel said glycerin feed from said nozzle;
 2. an impingement pin attached to said exterior of said nozzle, said impingement pin having a target surface positioned coaxially with said orifice and facing said orifice, said target surface being configured to diffuse said glycerin feed expelled through said orifice; iii. wherein said nozzle is configured to spray said atomized glycerin stream into a combustion chamber where said atomized glycerin stream is combusted; b. supplying said glycerin feed to said fuel supply line; and c. combusting said atomized glycerin stream in said combustion chamber.
 10. The method of combusting glycerin of claim 9, further comprising: a. providing an air supply line configured to supply an air feed to said burner; and b. providing a heat exchanger configured to preheat said air feed with heat produced from the combustion of said atomized glycerin stream before expelling said air feed from said burner.
 11. The method of claim 9, further comprising the step of supplying a mixture of a starter fuel and glycerin to said nozzle for a period of time.
 12. The method of claim 11, wherein said starter fuel comprises an alcohol.
 13. The method of combusting glycerin of claim 9, further comprising: a. providing an air supply line configured to supply an air feed to said burner; and b. providing a distributor in said interior of said nozzle, said distributor fluidly connected with said fuel feed line and said air supply line.
 14. The glycerin burning system of claim 13, said distributor configured to impart rotation to said air feed.
 15. The glycerin burning system of claim 13, said distributor having a fuel conduit fluidly connected to said fuel supply line, a plurality of air channels fluidly connected with said air supply line and a convergence region fluidly joining said plurality of air channels and said fuel conduit upstream of said orifice, said plurality of air channels configured to impart rotation to said air feed before said air feed passes through said orifice.
 16. The method of claim 9, further comprising: a. providing a water supply line configured to supply a water feed to said nozzle; b. purging said nozzle with water after combusting said atomized glycerin stream. 